The actor wandered into Adam Lindemann’s Madison Avenue gallery Venus Over Manhattan on Tuesday just before guests began arriving for a party there to celebrate Katie Couric and Laurie David’s documentary, “Fed Up.”

Spies said that Leo — who was with girlfriend Toni Garrn — had visited the gallery daily for 10 days straight to admire an exhibition of surfer paintings by punk icon-turned-top artist Raymond Pettibon.

“He’s been there in the middle of the day, strolling around looking at the art,” said a spy of Leo. “He’ll point something out and Toni’s just like, ‘Uh-huh, that’s nice.’ ”